On Android, tabs will not accept textAllCaps as false, why?

Based on some SO and another page, I added the ability to disable all caps on my tabs:

<style name="ScreenTransition.Activity" parent="@android:style/Theme.Holo.Light.NoActionBar"> 
    <item name="android:windowEnterAnimation">@anim/screen_in</item>
    <item name="android:windowExitAnimation">@anim/screen_out</item>
</style>

<style name="tabTheme" parent="@android:style/Widget.ActionBar.TabText">
    <item name="android:textAllCaps">false</item>
</style>

<style name="ScreenTransition" parent="@android:style/Theme.Holo.Light.NoActionBar">
    <item name="android:windowAnimationStyle">@style/ScreenTransition.Activity</item>
    <item name="android:actionBarTabTextStyle">@style/tabTheme</item>
</style>

I have this declared in my manifest:

<android:theme="@style/ScreenTransition" >

The first part handles the transitions on the screen that I want to use to style my tabs. I know that "ScreenTransition" is a bad theme name (now). I will change the name to something more general later.

My transitions work fine but don't apply

<item name="android:textAllCaps">false</item>